Biology Form 4 Chapter 7 Respiration

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THE RESPIRATORY STRUCTURE AND BREATHING MECHANISM OF HUMANS

1Biology Form 4 Chapter 7 Respiration 1

2DEFINITION The Respiratory system is the system that helps you breath in and out, so oxygen (02) can be pumped through your body and carbon dioxide (CO2) can be removed from the blood stream.

Biology Form 4 Chapter 7 Respiration 2

The Human Respiratory system

31.2.3.4.5.6.7.8.9.Biology Form 4 Chapter 7 Respiration 3


36.7.8.9.Biology Form 4 Chapter 7 Respiration 8

10 A large tube that is supported by C-shaped cartilages which keeps the trachea open permanently to receive air.

Epithelium cells of the trachea are lined with cilia. Between the epithelium cells are goblet cells which secrete mucus.

The mucus traps dust and microorganisms. Air is warmed to body temperature and moistened.

Air enters the bronchi.

TRACHEABiology Form 4 Chapter 7 Respiration 19


37.8.9.Biology Form 4 Chapter 7 Respiration 9

4 A human respiratory system consists of a series of tube-like structures connecting a pair of lungs to the atmosphere. The tube-like structures consists of a nasal passage, pharynx, larynx, trachea, bronchi (singular: bronchus) and bronchioles.

LUNGSBiology Form 4 Chapter 7 Respiration 13

5 The lungs are the large sac-like organs, which are made up of mainly the bronchioles, alveoli and a network of blood capillaries. The left lungs has two lobes while the right lung has three lobes.

LUNGSBiology Form 4 Chapter 7 Respiration 14

6PASSAGE OF AIRBiology Form 4 Chapter 7 Respiration

Air entersTonguePharynxTrachea is held open by C-shaped rings of cartilageNasal passageLarynx/voiceboxAirwayAlveoliBronchioles takes air to and from alveoliOuter surface of each alveolus is line with blood capillariesEpithelial cells enable 02 and CO2 to dissolve

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7NASAL PASSAGE OR NASAL CAVITY

Sphenoid sinusFrontal sinusNasal CavityBiology Form 4 Chapter 7 Respiration 16

NASAL PASSAGE OR NASAL CAVITY Air enters through the nostrils (nasal cavity) Dust and microorganisms are trapped by mucus and sweep towards the back of the mouth to be swallowed or coughed out. The inhaled air is warmed, filtered and moistened in the nasal cavity.


9TRACHEA / BRONCHI / BRONCHIOLE

Biology Form 4 Chapter 7 Respiration 18BRONCHIBiology Form 4 Chapter 7 Respiration

Two tubes which branch from the trachea Enters the left and right lungs respectively Is called bronchus in singular Traps the dust and microorganisms when the air passes by. Carries the air to the bronchioles

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MUCUSCILIA

CELLS

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12BRONCHIOLES Each bronchus subdivides repeatedly to form smaller tubes called bronchioles.

They lack cartilages.

Carries the air to the alveoli.


13ALVEOLI


14ALVEOLI Also called air-sacs. Small, moist, thin-walled air sacs (0.2 mm in diameters) Gaseous exchange between the blood and the lungs.


15GASEOUS EXCHANGE

Capillary wallRed blood cellOxygen is picked upCarbon dioxide is dropped offCapillaryBiology Form 4 Chapter 7 Respiration 24

16GASEOUS EXCHANGE


17ADAPTATION OF THE ALVEOLI FOR GASEOUS EXCHANGEi) A large surface area The total surface area of the alveoli in the lungs is about 75m2. This is 80 times the total skin surface area of an adult human.


18ii) Very thin walls The alveolar wall is only one-cell thick so that diffusion of oxygen and carbon dioxide can occur readily.


19iii) A moist surface The inner surfaces of the alveoli are covered with a thin layer of fluid. Gases have to dissolve in this fluid before they can diffuse across the alveolar wall.


20iv) A rich supply of blood 80% of the alveolar walls are covered with the blood capillaries. They provide a rich blood supply to transport gases to and from the alveoli.


21INHALATION / EXHALATION

Biology Form 4 Chapter 7 Respiration

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22INHALATION / EXHALATIONBiology Form 4 Chapter 7 Respiration

Air entersAir leavesLungs get smallerRib cage moves down and in.Lung expandsRib cage moves up and outexhalationinhalationDiaphragm moves upDiaphragm moves down

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23INHALATION The external intercostal muscles contract while the internal intercostal muscles relax. As a result, the ribs and sternum move upwards and outwards. The diaphragm muscles contract and the diaphragm flattens.


24INHALATION The movements of the rib cage and the diaphragm increase the volume of the thoracic cavity. Increasing the volume of the thoracic cavity lowers the pressure inside the thoracic cavity until it is less than the atmospheric pressure. Air is drawn into the lungs.

Biology Form 4 Chapter 7 Respiration 33EXHALATION The internal intercostal muscles constract while the external intercostal muscles relax. As a result, the ribs and sternum move downwards and inwards back to its resting position.

The diaphragm muscles relax and the diaphragm arches upwards.


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26EXHALATION The movements of the rib cage and the diaphragm decrease the volume of the thoracic cavity. Decreasing the volume of the thoracic cavity increases the pressure inside the thoracic cavity until it is greater than the atmospheric pressure. Air is forced out of the lungs.


27DIFFERENCES BETWEEN THE INHALATION AND EXHALATION


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1. What are two names for structure no. 9? i) Trachea ii) windpipe


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2.What is the structure that filters the air as it is inhaled?No. 1 Nasal Cavity Biology Form 4 Chapter 7 Respiration 38

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3. What is the no. and name of the muscle responsible for breathing?No. 6 diaphragmBiology Form 4 Chapter 7 Respiration 39

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4. Where does the actual exchange of oxygen and carbon dioxide takes place? Air sacs

5. Which of the following activities does not take place during inhalation? Ribs are pulled downloads

6. State four structures which are involved in the human gaseous exchange system? Trachea, bronchus, bronchiole, alveolus


32A MODEL OF THE HUMAN LUNGSProblem: How does the diaphragm help in breathing?

Hypothesis: Contraction of the diaphragm, muscles results in inhalation.

Materials: Rubber sheet, balloons and string.

Apparatus: Bell jar, glass tube and bung with one hole.


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Figure 1Biology Form 4 Chapter 7 Respiration 42

34Method: 1. A balloon is tied to the tube.2. The apparatus is set up as shown in Figure 1.3. The rubber sheet is stretched across the open end of the bell jar.4. The change in size of the balloon is recorded when the rubber sheet is pulled downwards and pushed upwards.Biology Form 4 Chapter 7 Respiration 43When the rubber sheet is pulled downwards, the balloons expanded.When the rubber sheet is pushed upwards, the balloons contracted.

The diaphragm contracts (when the rubber sheet is pulled downwards) during inhalation.

Biology Form 4 Chapter 7 Respiration

35Results

Conclusion

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Parts of the bell jar model that represent parts of the human respiratory system.

Biology Form 4 Chapter 7 Respiration tubeballoonRubber sheetBell jarBELL JARMODEL45

37Discuss the similarities and differences between ahuman respiratory system with that of other organisms:-

Group A ~ fish

Group B ~ frog

Group C~ insectBiology Form 4 Chapter 7 Respiration Homework 46Internet Reference:1. http://yucky.kids.discovery.com/flash/body /pg000138.html2. http://www.lung.ca/children/grades7_12 /respiratory/index.html3. http://www4.tpgi.com.au/users/amcgann/body /respiratory.html4. http://www4.tpgi.com.au/users/amcgann/body /respiratory_facts.html5. http://users.pandora.be/educypedia/education /respiratory.htm6. www.geocities.com/medinotes/nasal_cavity.htm

38Biology Form 4 Chapter 7 Respiration 47

Reference Books:

Gan Wan Yeat, Biology Form 4, Bakaprep Sdn. Bhd. Petaling Jaya 2005

2. Gan Wan Yeat, Biology Form 4: Practical Book, Bakaprep Sdn. Bhd. Petaling Jaya, 2005

Memory Mastery Through Mind Maps Diagrams Biology SPM, PNI Neuron Sdn. Bhd. Selangor, 200639Biology Form 4 Chapter 7 Respiration

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Biology Form 4 Chapter 7 Respiration